#!/bin/sh

mkdir -p ~/.gosh
data=~/.gosh/data
hist=~/.gosh/history
type=~/.gosh/type

# selector, host, port
fetch() {
	printf '%s\n' "$2" | grep -q '[a-z]' || return 1
	printf '%s\r\n' "$1" | nc "$2" "$3" > "$data" 2>/dev/null
}

# type, selector, host, port
metafetch() {
	fetch "$2" "$3" "$4" || return 1
	printf '%s\n' "$1" > "$type"
	printf '%s%s\t%s\t%s\t%s\r\n' \
	       "$1" "$(date -Is)" "$2" "$3" "$4" >> "$hist"
}

gophermap_transform() {
	awk -F '\t' '
		/^i/     { printf("\t%s\n", substr($1, 2)) }
		/^[^i.]/ { printf("%d\t%s\n", ++n, substr($1, 2)) }
	'
}

view() {
	local viewer
	case "$(cat "$type")" in
	0) less -E -X "$data";;
	1) gophermap_transform < "$data" | less -E -X;;
	*)
		printf '? '
		trap 'echo; return 1' INT
		read viewer || echo
		trap - INT
		[ "$viewer" ] || return 1
		sh -c "$viewer" < "$data"
		;;
	esac	
}

# type, filename, number
follow() {
	local line sep chr1 sltr host port
	[ "$1" = 1 ] || return 1
	line="$(grep '^[^i.]' "$2" 2>/dev/null | sed -n "$3p" | tr -d '\r')"
	[ "$line" ] || return 1
	sep="$(printf '\t')"
	chr1="$(printf '%s\n' "$line" | cut -c1)"
	sltr="$(printf '%s\n' "$line" | cut -d"$sep" -f2)"
	host="$(printf '%s\n' "$line" | cut -d"$sep" -f3)"
	port="$(printf '%s\n' "$line" | cut -d"$sep" -f4)"
	metafetch "$chr1" "$sltr" "$host" "$port"
}

back() {
	printf '$-1,$m0\nwq\n' | ed "$hist" >/dev/null
	follow 1 "$hist" 1 && view
}

while :
do
	printf '> '
	trap 'echo; continue' INT
	read -r cmd || break
	trap - INT
	case "$cmd" in
	q ) exit;;
	'') view;;
	b ) back;;
	* )
		if printf '%s\n' "$cmd" | grep -q '^[1-9][0-9]*$'
		then follow "$(cat "$type")" "$data" "$cmd" && view
		else metafetch 1 '' "$cmd" 70 && view
		fi
		;;
	esac
done
printf '\n'